So... This is the "improved encounter design"?

[Shurrikhan]

There is obviously the slidecasting element to that so I'm not entirely sure how caster uptime could be constrained

A small note that may be of use:

Everyone has access to 100% uptime, technically, regardless of content, due to fall-back options. It's effective uptime, the portion of maximum striking dummy DPS or the available positioning required for that, that differs with context.

Some variance in the term effective uptime:

• Can be used to describe actual portion of damage produced, in which case it's basically just %yield.
• Can be used to describe just one's potential for output rather than actual output, including positional access.
• Can be used to describe only what requires melee range / standing time, rather than positionals or anything outside of one's control beyond those two concerns (interested more in basic potential than real output).